Quality performance measurement and improvement have been in place for AMI for several years, particularly within the process-of-care domain. Through the use and analysis of these measures, physicians, hospitals, oversight agencies, researchers, and consumers have learned about how quality care can be measured, about variability in care, and about the effectiveness of current practice patterns. Most importantly, quality performance measurement for AMI has provided a focus and direction for those devoted to improving care. Despite evidence of early success from these efforts, there remains substantial additional work yet to do. The Working Group believes that if the true potential for American health care is to be realized, substantial national funding and support for strengthening the scientific foundation of quality measurement and improvement are needed for our country to effectively translate the accumulating evidence of medicine into routine clinical practice.